Intermittent Type Reaction Vessel Temperature Predictive Control

With the development of our national economy rapidly, the petrochemical industry is on the upgrade. The synthetic resin, one of main products of petrochemical industry, is used in many fields. As synthetic resin acts a vital role in national economy, higher requests are put forward to meet the need of the higher production quality and industry process automation. The polymerization of synthetic resin like polypropylene, polyethylene, and phenolic resin etc, largely reacts in the intermittent type reaction vessel, account for 90%. Of all the parameters, temperature is the most important parameter, deciding on the quality and production. The process of polymerization is both the exothermic chemical reaction process and the physical change process, the mechanism of polymerization is very complex. The process of polymerization have the characteristics such as the great inertia, time-delaying, time-varying, when refrigeration and heating cut the furnace temperature undulates in a big way, and nonlinearity serious etc, so it is very difficult to establish the accurate mathematical model of the object, and also very hard to control the temperature of the industry process by traditional PID control theory and step control mode.This dissertation is devoted to controlling the temperature of intermittent type reaction vessel. The characteristics and controlling difficulty of reaction vessel temperature control have been analyzed comprehensively, and the precision difference basic reason of current temperature control system has been summarized. The paper uses the linear least squares method and the generalized predictive principle, based on the king view software platform made by Beijing Yakong Company, and designs a simple practical solution, which use PID control at temperature rising stage, and then use the generalized predictive control at the stage of 60～70℃when refrigeration and heating cut to solve the vibration which the serious non-linearity brings. The experiment indicates that, comparing with the PID control plan, this plan strengthens the system robustness and adaptability, and the oscillation amplitude of system decreases 0.83℃. The design of the hardware circuit, as well as the editing and debugging of the system software of the intermittent type reaction vessel have been achieved in this issue; and simulation and experiment study have been done, comparing with the PID control plan, the control performance of five step Generalized Predictive Control is more steady ,and reliability better than others, real-time, adaptability, robustness get better by identifying the mathematical model of object online and outline, the control effect is favorable.